Conventional fireplaces are not very effective sources of heat for the room in which they are located primarily because the fire draws heated air from the room and large amounts of outside air into the house to meet the combustion requirements of the fire. This causes drafts of cold air along the floor of the room and the cooling of the house.
As is described in my copending application, Ser. No. 34,424, the heating effectiveness of a fireplace is greatly increased by the provision of an air distributor in cooperation with means for supplying outside air to an opening in the hearth of the fireplace. The air supply may comprise a flow path including the ash pit opening in the hearth with the air being supplied from the basement or other house area whereby relatively cold air is supplied to the fire. Also, the ash pit opening may be supplied with air from the outside of the house. The air distributor is constructed and arranged to be positioned to direct the flow of air passing through the hearth opening toward the front opening of the combustion chamber for discharge at that location so that the air passes to the fire to meet the combustion requirements thereof and upwardly through the chimney flue. Accordingly, relatively cold outside air is supplied to the fire to support the combustion thereof thereby substituting this cold air for the room air which conventional fireplaces utilize to feed the fire. Since the room air is normally heated by the home's heating system, the use of much less energy to feed the fire results in considerable savings in energy.
A further improvement to the above-described arrangement is to provide means for circulating the room air through the combustion chamber of the fireplace to draw heat from the combustion gases which would normally pass up the flue without providing any heating action to the room. While heat exchangers for room air are known, those in general use today have several disadvantages. For example, such prior art heat exchangers are generally large and cumbersome and are located at least partially near the bottom region of the combustion chamber. Also, when the prior art heat exchangers are inserted in existing fireplace openings, they severely limit the size of the viewing area and access doors.
It is the general object of the invention to provide a fireplace system for heating the room air by the use of a compact, heat exchanger which is light in weight and adapted to be installed in existing fireplaces.
A further object of the invention is to provide a heat exchanger of the indicated type which is constructed to provide a more complete combustion and a highly efficient heat exchange action. To this end the combustion gases are caused to spin with induced Coriolis forces while being exposed to a hot catalytic plate on their interior. Furthermore, the exterior of these hot spinning gases will have repeated exposure to the highly conductive heat exchanger wall for additional extraction of heat making the device extremely efficient in the removal of energy from the exhaust gases just before entry into the chimney flue.
A further object of the invention is to provide a heat exchanger construction which can be easily removed after a period of service for cleaning or the like.
Briefly stated, the fireplace heating system in accordance with the invention includes a heat exchanger, means for mounting the heat exchanger at the top portion of the combustion chamber to extend across a location where the chimney flue connects with the top portion of the combustion chamber, and fan means for circulating room air through the heat exchanger. The heat exchanger comprises means defining a heat exchange passage for the flow of room air and means defining a heat exchange and spin inducing passage for the flow of combustion gases from the combustion chamber to the chimney flue, such heat exchange passages being in heat exchange relationship so that the hot combustion gases heat up the room air being circulated through the heat exchanger by the fan means.